In addition to the application of DC charger in electric vehicles and charging piles, it is also widely used in the fields of AGV unmanned sorting vehicles, energy storage equipment, solar power generation equipment, construction equipment and power control.
Energy storage system
Energy storage system is one of the fastest developing fields in recent years. New energy allows power to be generated anytime, anywhere, not just on demand. Therefore, it is very important to cover and support the demand peak and balance the demand of energy backup system for power generation and demand. The popularity of electric vehicles also needs to have a profound impact on the public power network, because fast charging requires a high energy peak. The energy storage system can reduce the impact on the public grid. Energy storage system is in the process of continuous development, in the aspect of high-voltage DC, the new DC contactor is the focus of this technical field.
Schematic diagram of energy storage system
When the common contactor is connected to the DC circuit, it will produce an arc. However, the electric arc keeps the circuit closed, which will wear the contact and reduce the service life of the contactor. There are different technologies in the market to solve this problem. Inert gas (non ionizing medium) is added to gas encapsulated contactor to reduce arc and contact loss. This solution allows the size to be reduced, but the gas will overheat. When high current passes through, overload of DC circuit may cause overheating, overvoltage or even explosion.
Another kind of DC contactor with magnet arc extinguishing can avoid these defects. The magnet drives the arc away from the contact point and extinguishes it in a compact arc extinguishing hood. The open arc extinguishing hood is used to deal with the arc, without the risk of overpressure and explosion. It can be realized in a very small size.
With the development of the solar energy industry, large-scale solar photovoltaic plants with installed capacity are also developing rapidly. People also put forward higher and higher requirements for the performance of the control and protection appliances in large-scale solar photovoltaic power plants. When the power of photovoltaic power plant exceeds a certain level, it needs circuit breaker or disconnector, especially the protection and isolation of inverter. DC contactor is generally installed in photovoltaic combiner box and DC cabinet.
Photovoltaic power generation
The DC contactor keeps the switch state unchanged by the magnetic force of the magnetic steel, and the coil does not consume electricity. Therefore, the contact pressure of the contact is large, the contact resistance is small, the vibration and impact resistance are resistant, the action voltage range is wide, sensitive and reliable, the volume is small, and it can work with large load for a long time.
There are many advantages of using DC contactor. First, the wiring is very convenient, and there is no tripping problem. Second, the cost can be effectively reduced without the need for series copper bars, cables and combiner boxes. Third, small volume and weight, long service life.